Olding, Simon, author
Her Majesty's Stationary Office, 1989
Buku Referensi
Franks, Norman L.R.
William Kimber, 1980
Buku Teks
Heidensohn, Frances, author
Macmillan, 1989
Buku Teks
Fowler, Peter J., author
Routledge, 1995
Buku Teks
Philo, Greg
Routledge, 1990
Buku Teks